From b22da3d8526a935aa31e086e63f60ff3246cb61c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 07:24:11 +0000
Subject: [PATCH] add stmac read mac form eeprom
---
kernel/arch/mips/include/asm/cmpxchg.h | 170 +++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 141 insertions(+), 29 deletions(-)
diff --git a/kernel/arch/mips/include/asm/cmpxchg.h b/kernel/arch/mips/include/asm/cmpxchg.h
index 520ca16..3e9c41f 100644
--- a/kernel/arch/mips/include/asm/cmpxchg.h
+++ b/kernel/arch/mips/include/asm/cmpxchg.h
@@ -11,18 +11,9 @@
#include <linux/bug.h>
#include <linux/irqflags.h>
#include <asm/compiler.h>
+#include <asm/llsc.h>
+#include <asm/sync.h>
#include <asm/war.h>
-
-/*
- * Using a branch-likely instruction to check the result of an sc instruction
- * works around a bug present in R10000 CPUs prior to revision 3.0 that could
- * cause ll-sc sequences to execute non-atomically.
- */
-#if R10000_LLSC_WAR
-# define __scbeqz "beqzl"
-#else
-# define __scbeqz "beqz"
-#endif
/*
* These functions doesn't exist, so if they are called you'll either:
@@ -36,6 +27,8 @@
*/
extern unsigned long __cmpxchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for cmpxchg");
+extern unsigned long __cmpxchg64_unsupported(void)
+ __compiletime_error("cmpxchg64 not available; cpu_has_64bits may be false");
extern unsigned long __xchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for xchg");
@@ -47,17 +40,19 @@
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
+ " .set push \n" \
" .set " MIPS_ISA_ARCH_LEVEL " \n" \
+ " " __SYNC(full, loongson3_war) " \n" \
"1: " ld " %0, %2 # __xchg_asm \n" \
- " .set mips0 \n" \
+ " .set pop \n" \
" move $1, %z3 \n" \
" .set " MIPS_ISA_ARCH_LEVEL " \n" \
" " st " $1, %1 \n" \
- "\t" __scbeqz " $1, 1b \n" \
+ "\t" __SC_BEQZ "$1, 1b \n" \
" .set pop \n" \
: "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
: GCC_OFF_SMALL_ASM() (*m), "Jr" (val) \
- : "memory"); \
+ : __LLSC_CLOBBER); \
} else { \
unsigned long __flags; \
\
@@ -99,7 +94,13 @@
({ \
__typeof__(*(ptr)) __res; \
\
- smp_mb__before_llsc(); \
+ /* \
+ * In the Loongson3 workaround case __xchg_asm() already \
+ * contains a completion barrier prior to the LL, so we don't \
+ * need to emit an extra one here. \
+ */ \
+ if (__SYNC_loongson3_war == 0) \
+ smp_mb__before_llsc(); \
\
__res = (__typeof__(*(ptr))) \
__xchg((ptr), (unsigned long)(x), sizeof(*(ptr))); \
@@ -117,19 +118,21 @@
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
+ " .set push \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
+ " " __SYNC(full, loongson3_war) " \n" \
"1: " ld " %0, %2 # __cmpxchg_asm \n" \
" bne %0, %z3, 2f \n" \
- " .set mips0 \n" \
+ " .set pop \n" \
" move $1, %z4 \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
" " st " $1, %1 \n" \
- "\t" __scbeqz " $1, 1b \n" \
+ "\t" __SC_BEQZ "$1, 1b \n" \
" .set pop \n" \
- "2: \n" \
+ "2: " __SYNC(full, loongson3_war) " \n" \
: "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
- : GCC_OFF_SMALL_ASM() (*m), "Jr" (old), "Jr" (new) \
- : "memory"); \
+ : GCC_OFF_SMALL_ASM() (*m), "Jr" (old), "Jr" (new) \
+ : __LLSC_CLOBBER); \
} else { \
unsigned long __flags; \
\
@@ -183,9 +186,23 @@
({ \
__typeof__(*(ptr)) __res; \
\
- smp_mb__before_llsc(); \
+ /* \
+ * In the Loongson3 workaround case __cmpxchg_asm() already \
+ * contains a completion barrier prior to the LL, so we don't \
+ * need to emit an extra one here. \
+ */ \
+ if (__SYNC_loongson3_war == 0) \
+ smp_mb__before_llsc(); \
+ \
__res = cmpxchg_local((ptr), (old), (new)); \
- smp_llsc_mb(); \
+ \
+ /* \
+ * In the Loongson3 workaround case __cmpxchg_asm() already \
+ * contains a completion barrier after the SC, so we don't \
+ * need to emit an extra one here. \
+ */ \
+ if (__SYNC_loongson3_war == 0) \
+ smp_llsc_mb(); \
\
__res; \
})
@@ -203,13 +220,108 @@
cmpxchg((ptr), (o), (n)); \
})
#else
-#include <asm-generic/cmpxchg-local.h>
-#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
-#ifndef CONFIG_SMP
-#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
-#endif
-#endif
-#undef __scbeqz
+# include <asm-generic/cmpxchg-local.h>
+# define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+
+# ifdef CONFIG_SMP
+
+static inline unsigned long __cmpxchg64(volatile void *ptr,
+ unsigned long long old,
+ unsigned long long new)
+{
+ unsigned long long tmp, ret;
+ unsigned long flags;
+
+ /*
+ * The assembly below has to combine 32 bit values into a 64 bit
+ * register, and split 64 bit values from one register into two. If we
+ * were to take an interrupt in the middle of this we'd only save the
+ * least significant 32 bits of each register & probably clobber the
+ * most significant 32 bits of the 64 bit values we're using. In order
+ * to avoid this we must disable interrupts.
+ */
+ local_irq_save(flags);
+
+ asm volatile(
+ " .set push \n"
+ " .set " MIPS_ISA_ARCH_LEVEL " \n"
+ /* Load 64 bits from ptr */
+ " " __SYNC(full, loongson3_war) " \n"
+ "1: lld %L0, %3 # __cmpxchg64 \n"
+ " .set pop \n"
+ /*
+ * Split the 64 bit value we loaded into the 2 registers that hold the
+ * ret variable.
+ */
+ " dsra %M0, %L0, 32 \n"
+ " sll %L0, %L0, 0 \n"
+ /*
+ * Compare ret against old, breaking out of the loop if they don't
+ * match.
+ */
+ " bne %M0, %M4, 2f \n"
+ " bne %L0, %L4, 2f \n"
+ /*
+ * Combine the 32 bit halves from the 2 registers that hold the new
+ * variable into a single 64 bit register.
+ */
+# if MIPS_ISA_REV >= 2
+ " move %L1, %L5 \n"
+ " dins %L1, %M5, 32, 32 \n"
+# else
+ " dsll %L1, %L5, 32 \n"
+ " dsrl %L1, %L1, 32 \n"
+ " .set noat \n"
+ " dsll $at, %M5, 32 \n"
+ " or %L1, %L1, $at \n"
+ " .set at \n"
+# endif
+ " .set push \n"
+ " .set " MIPS_ISA_ARCH_LEVEL " \n"
+ /* Attempt to store new at ptr */
+ " scd %L1, %2 \n"
+ /* If we failed, loop! */
+ "\t" __SC_BEQZ "%L1, 1b \n"
+ "2: " __SYNC(full, loongson3_war) " \n"
+ " .set pop \n"
+ : "=&r"(ret),
+ "=&r"(tmp),
+ "=" GCC_OFF_SMALL_ASM() (*(unsigned long long *)ptr)
+ : GCC_OFF_SMALL_ASM() (*(unsigned long long *)ptr),
+ "r" (old),
+ "r" (new)
+ : "memory");
+
+ local_irq_restore(flags);
+ return ret;
+}
+
+# define cmpxchg64(ptr, o, n) ({ \
+ unsigned long long __old = (__typeof__(*(ptr)))(o); \
+ unsigned long long __new = (__typeof__(*(ptr)))(n); \
+ __typeof__(*(ptr)) __res; \
+ \
+ /* \
+ * We can only use cmpxchg64 if we know that the CPU supports \
+ * 64-bits, ie. lld & scd. Our call to __cmpxchg64_unsupported \
+ * will cause a build error unless cpu_has_64bits is a \
+ * compile-time constant 1. \
+ */ \
+ if (cpu_has_64bits && kernel_uses_llsc) { \
+ smp_mb__before_llsc(); \
+ __res = __cmpxchg64((ptr), __old, __new); \
+ smp_llsc_mb(); \
+ } else { \
+ __res = __cmpxchg64_unsupported(); \
+ } \
+ \
+ __res; \
+})
+
+# else /* !CONFIG_SMP */
+# define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
+# endif /* !CONFIG_SMP */
+#endif /* !CONFIG_64BIT */
#endif /* __ASM_CMPXCHG_H */
--
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